1. Field of the Invention
The present invention relates to wireless network communications and, more particularly to transmission of media to multiple subscribers in a wireless communications network.
2. Description of Related Art
The art and popularity of wireless communication devices has grown significantly over recent years. Indeed, millions of people are engaging in voice and data communications over wireless communication devices such as cellular telephones and Personal Digital Assistants (PDAs). In principle, a user can communicate over the Internet or call anyone over the Public Switched Telephone Network (PSTN) from any place inside the coverage area of a cellular wireless network.
In a typical cellular wireless network, an area is divided geographically into a number of cells and cell sectors, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS) antenna. The base station antennae in the cells are in turn coupled to a base station controller (BSC), which is then coupled to a telecommunications switch or gateway, such as a mobile switching center (MSC) or packet data serving node (PDSN) for instance. The switch or gateway may then be coupled with a transport network, such as the PSTN or a packet-switched network (e.g., the Internet). Conveniently with this arrangement, when a wireless communication device is positioned within a given sector, the device can communicate with entities on the transport network via a communication path comprising the BTS, the BSC, the switch or gateway, and the transport network.
Generally, each sector or other coverage area in a wireless communication system will have a limited extent of radio frequency resources. In a traditional CDMA system, for instance, the air interface for transmissions from a BTS to served devices is divided into a limited number of channels, each defined by a respective “Walsh code.” Thus, each wireless coverage area can support only a finite extent of communications traffic at once.
This limitation can be particular problematic in the context of wireless packet-data communications. In a typical cellular wireless communication system, for instance, when a wireless communication device is to engage in packet-data communications, the device will enter into an “active” state by acquiring (i) a reserved air interface traffic channel, (ii) a data link with a network gateway, and (iii) an IP address for engaging in IP-based communications. After the device finishes sending and receiving packet data, however, the device's reserved air interface traffic channel will typically remain reserved for a period of time known as the “active-to-dormant” time period, so as to enable the device to engage in further packet-data communications. As a result of this active-to-dormant time period, air interface resources may be tied up even for devices that are not currently engaging in packet-data communications, thus further limiting the resources available for use by other devices.